瞬变电磁波测井井旁异常体定量表征方法研究  

Research on quantitative characterization method of near-well anomalies in transient electromagnetic logging

作　　者：刘宇轩 范宜仁[1,2] 胡旭飞 邓少贵 赵东玥[1,2] LIU YuXuan;FAN YiRen;HU XuFei;DENG ShaoGui;ZHAO DongYue(School of Geosciences,China University of Petroleum,Qingdao 266580,China;CNPC Key Laboratory for Well Logging,China University of Petroleum,Qingdao 266580,China;School of Civil Engineering and Architecture,Wuyi University,Jiangmen 529020,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,青岛266580 [2]中国石油大学CNPC测井重点实验室,青岛266580 [3]五邑大学土木建筑学院,江门529020

出　　处：《地球物理学进展》2025年第1期304-317,共14页Progress in Geophysics

基　　金：国家自然科学基金项目(41974146,42074134,U23B2086);新疆维吾尔自治区科技厅自然科学基金青年项目(2020D01B63);新疆维吾尔自治区教育厅高校科研计划项目(XJEDU2021Y052)联合资助.

摘　　要：瞬变电磁波测井是地下介质探测的重要方法之一,特别适用于井旁异常体的探测.然而,井旁异常体的电磁响应多种多样且复杂,急需一种精确定位和定量表征的方法.这种方法要能准确识别异常体的关键属性,如位置、形状、尺寸和电性质,并提供定量描述.本文采用三维时域有限差分方法研究了均匀地层、水平层状异常体和三维块状异常体的瞬变电磁场响应,对异常体的电阻率和位置等因素进行了考察,了解其对测量响应的影响.通过分析散射体产生的响应,揭示了层状介质的延伸情况,以及三维块状孤立异常体的位置、大小和响应规模的重要信息.基于全区视电阻率反演方法,提出了层状井旁异常体电性剖面反演技术.针对全区视电阻率反演方法在晚期信号无法准确反映地层电阻率真实变化的问题,提出了结合梯度寻优算法的纵向地层电阻率剖面反演方法.此外,采用烟圈反演算法,实现三维块状异常体电性剖面反演.改进的探测方法可实现井旁异常体的定量表征,显著提高了井旁孤立异常体位置和电性提取的精度,整体表征误差小于5%.这种改进的探测方法对石油和固体矿产勘探具有重要意义,有助于确定油气和固体矿产资源的分布和储量.能够指导勘探活动的决策和优化资源开发方案,从而提高井旁异常体探测的精度和可靠性.同时,准确探测地下异常体有助于了解地下结构特性,指导工程设计和施工,提高工程建设的效率和安全性.Transient electromagnetic wave logging is one of the important methods for subsurface media detection,especially suitable for detecting anomalies near wells.However,the electromagnetic response of wellbore anomalies is diverse and complex,demanding a precise positioning and quantitative characterization method.This method needs to accurately identify key attributes of the anomalies,such as their position,shape,size,and electrical properties,and provide quantitative descriptions.In this study,the three-dimensional Finite Difference Time Domain(FDTD)method in the time domain is employed to investigate the transient electromagnetic field responses of homogeneous formations,horizontally layered anomalies,and three-dimensional block anomalies.Factors such as anomaly resistivity and position are examined to understand their influence on the measurement responses.By analyzing the responses generated by scattering bodies,important information regarding the extension of layered media and the position,size,and response magnitude of three-dimensional isolated anomalies is revealed.A layered wellbore anomaly electrical profile inversion technique is proposed based on the full-area apparent resistivity inversion method.To address the issue of late signals in the full-area apparent resistivity inversion method that cannot accurately reflect the true variation of formation resistivity,a direct vertical partition inversion combining gradient optimization algorithm is proposed.Additionally,a smoke ring inversion algorithm is employed for three-dimensional block anomaly electrical profile inversion.The improved detection method achieves quantitative characterization of wellbore anomalies,significantly improving the accuracy of positioning and electrical property extraction of isolated anomalies near wells,with an overall characterization error of less than 5%.This improved detection method is of great significance for petroleum and solid mineral exploration,aiding in determining the distribution and reserves of oil,gas,and solid m

关 键 词：瞬变电磁波测井 时域有限差分 井旁异常体 视电阻率反演 异常体定量表征 

分 类 号：P631[天文地球—地质矿产勘探]